Tohoku J. Exp. Med., 2007, 213(1)

Expression of Angiopoietin-2 is Correlated with Vascularization and Tumor Size in Human Colorectal Adenocarcinoma

HONG-LING WANG,¹ CHANG-SHENG DENG,¹ JUN LIN,¹ DING-YU PAN,² ZU-YU ZOU³ and XIAO-YANG ZHOU⁴

¹Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, China
²Department of General Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
³Department of Pathology, Zhongnan Hospital of Wuhan University, Wuhan, China
⁴Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China

Angiopoietins are endothelial growth factors, which play crucial roles in normal vascular development and tumor angiogenesis. We examined the expression profiles of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), vascular endothelial growth factor (VEGF), and Tie-2, a receptor for Ang-1 and Ang-2, in both colorectal adenocarcinoma and adjacent normal tissues, as judged by histology, in order to elucidate their relationships with microvascular density (MVD) and clinicopathologic properties. Higher MVD was associated with a lower degree of differentiation of colorectal adenocarcinoma. Immunohistochemical analysis revealed that the expression of Ang-2 and VEGF was significantly increased in colorectal adenocarcinoma compared to adjacent normal tissues (p < 0.01), and the expression of Ang-2 positively correlated with that of VEGF (r = 0.997, p < 0.01). In contrast, the expression of Ang-1 was lower in adenocarcinoma tissues than in adjacent normal tissues (p < 0.01), while there was no significant difference in Tie-2 expression in both tissues. Moreover, MVD was increased in Ang-2- and VEGF-expressing adenocarcinoma tissues compared to the Ang-2- and VEGF-negative tissues, respectively (p < 0.01). Importantly, MVD was lower in Ang-1-expressing adenocarcinoma tissues relative to Ang-1-negative tissues (p < 0.01). Furthermore, expression of Ang-2 as well as VEGF was significantly up-regulated in colorectal adenocarcinoma with diameters ≥ 5 cm or with lymph-node metastases (p < 0.01). In conclusion, the increased expression of Ang-2 and the decreased expression of Ang-1 may be responsible for blood vessel formation and rapid growth of the colorectal adenocarcinoma.

keywords —— angiopoietins; colorectal adenocarcinoma; microvascular density; clinicopathology

© 2007 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2007, 213, 33-40

Correspondence: Chang-Sheng Deng, Department of Gastroenterology, Zhongnan Hospital, Wuhan University, Wuhan 430071, Hubei Province, China.

e-mail: zhnwhl@yahoo.com.cn